Electronic message delivery system utilizable in the monitoring of remote equipment and method of same

ABSTRACT

A system and method for monitoring remote equipment such as HVAC equipment, are provided. A sensor is in communication with a piece of remote equipment. An interface unit, having a message generating mechanism, is capable of receiving signals from the sensors. The interface unit is provided with a programmable logic controller which performs Boolean operations or expressions on the signals received by the sensors. A central computer server is in communication with the interface unit and is adapted to receive and preferably store messages generated by the interface unit. When a sensor detects an exception condition in a piece of remote equipment, the sensor transmits a signal to the interface unit, and the interface unit generates an incoming exception message and forwards the message to the server. The server forwards at least one outgoing exception message to at least one predetermined user-defined communication device based on the incoming exception message. Multiple outgoing exception messages may be forwarded to multiple communication devices in accordance with a user-defined message profile, or a single outgoing exception message may be forwarded in response to receipt of multiple incoming exception messages. The message profile is remotely configurable by the user.

RELATED APPLICATIONS

This is a Continuation-in-Part application of U.S. patent applicationSer. No. 09/317,235, filed May 24, 1999 and U.S. patent application Ser.No. 09/401,460, filed Sep. 22, 1999, and claims priority from U.S.Provisional Patent Application No. 60/115,305, filed Jan. 4, 1999.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to monitoring systems, and more specifically tonetworks for remotely monitoring the condition of devices such as thoseemployed in heating, ventilating, and cooling (HVAC) systems.

2. Description of the Related Art

It is desirable to be able to monitor remotely equipment that mayrequire periodic preventive maintenance and/or that may require rapidresponse time should a catastrophic failure occur. For example, thecomponents of a building's HVAC system must be monitored or checkedfrequently. Preventive maintenance must be performed on a constantbasis, particularly with larger systems. Fault or failure conditions mayvary in degrees of severity, however the contractor responsible formaintaining the HVAC equipment should be made aware of each failure indue course. Since a contractor, in all likelihood, is responsible forthe care and maintenance of the installations of multiple clients, andsince fault conditions may occur at any time of day or night, it is notpractical for a contractor to remain on-site all the time. Remotedetection at a central location (for example, the contractor's office)of fault conditions is desirable and often crucial.

It is further desirable to be able to activate or deactivate a piece ofequipment remotely or send it commands remotely. It is also desirable toknow the approximate failure rate or frequency of failure of each pieceof equipment. One can make installation recommendations as to whichmodel or brand of equipment is best suited for a particular site, andone can anticipate the failure of an already-installed piece ofequipment and specific components therein based on how long it isrunning.

Some remote monitoring devices have been developed. U.S. Pat. No.5,629,687 to Sutton et al. describes a universal interface forremotely-monitored security or alarm systems. In Sutton et al., a localcontrol unit at a monitored site can, under an event condition, initiatea telephone call to a central control unit to alert a human operator ofan event such as an intrusion, fire, or other emergency at the site. Thelocal control unit, via the telephone link, sends a serial numberindicative of the specific site and emergency to the monitoring centercomputer. The monitoring center computer receives the serial number andalerts a human operator as to the emergency. The human operator can thenact accordingly, e.g., establish one- or two-way communication with thelocal site.

U.S. Pat. No. 5,748,104 to Argyroudis et al. describes a wireless remotetelemetry system which provides real-time reading and remote control ofdevices such as electricity meters. A home base unit communicates withremote metering units via cellular telephone lines. The home base unitalso communicates with a central controller operated by the electricutility. When the utility determines that there is too much load on thepower grid, for example, the central controller can send messages to anappliance to turn off. A customer could also remotely activate ordeactivate an appliance via a cellular phone through the home base unit.

U.S. Pat. No. 5,061,916 to French et al. describes a system for remotelyreporting, in graphical format, alarms or other conditions in abuilding's automation system. Sensors in a building are hooked up via atelephone line to control module which is, in turn, hooked up to acentral controller. When a sensor detects a fault condition, graphicalinformation is compiled at the central controller and transmitted to oneor more remote facsimile machines.

All of the above systems and the prior art are limited in scope becausethey do not allow for sufficient flexibility in routing fault messagesto a variety of different potential recipients of such messages via avariety of different media, depending on the urgency or nature of thefault. Also, the above systems and the prior art do not enable customersand contractors to enter or modify such information easily. As anexample, a customer that has an HVAC system with a monitoring networkmay want to send certain non-emergency condition notifications (e.g.,filter needs cleaning) to certain individuals (e.g.,contractor/maintenance personnel) via a certain medium (e.g., e-mail)and emergency condition notifications (e.g., low or high refrigerantpressure) to other individuals (building owner, contractor, etc.) viaother means (e.g., via beeper or other personal communication device).Such a list of who to contact via what means depending on which faulthas occurred may be referred to as a “message profile”. The conventionaldevice/contractor interface requires a dedicated land line at both theHVAC device and the contractor; that is, the HVAC system requires itsown phone line, and the contractor must have a dedicated modem line aswell. Moreover, the conventional system does not allow for easy customermodifications to the message profile. The conventional systems also donot allow the user to determine the failure rate of the equipment or todetermine which pieces of equipment are best suited for a specific site.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the invention to provide a system forremotely monitoring electrical and/or mechanical equipment.

It is another object of the invention to provide a system for remotelymonitoring multiple pieces of electrical and/or mechanical equipment ina cost-effective manner.

It is another object of the invention to provide a system for remotelymonitoring electrical and/or mechanical equipment that can delivermessages to different individuals for different fault conditions.

It is another object of the invention to provide a system for remotelymonitoring electrical and/or mechanical equipment that can deliver faultnotification messages to different individuals for different faultconditions via different electronic media.

It is another object of the invention to provide a system for remotelymonitoring electrical and/or mechanical equipment in which a customermay interactively modify its message profile.

It is another object of the invention to provide a system for remotelymonitoring electrical and/or mechanical equipment in which a customermay interactively modify its message profile via the Internet.

It is another object of the invention to provide a system for remotelymonitoring electrical and/or mechanical equipment in which a user mayinteractively alter the operation of a piece of equipment remotely.

It is another object of the invention to provide a system for remotelymonitoring electrical and/or mechanical equipment in which thefunctional logic may be modified.

It is another object of the invention to provide a system for remotelymonitoring electrical and/or mechanical equipment which can collect dataover time concerning the monitored equipment.

The above and other objects are satisfied by the invention which is aremote equipment monitoring system and method for monitoring remoteequipment. In the inventive method, the respective states of a pluralityof parameters of at least one piece of remote equipment, such asheating, ventilating, and cooling equipment, are determined via aplurality of sensors. The information detected or gleaned from thesensors is grouped via ladder logic, preferably in the form of aprogrammable logic controller (PLC). Messages regarding the groupedinformation are communicated from the remote equipment to a centrallocation as incoming messages. Outgoing exception messages are forwardedbased on the incoming messages to at least one user-definedcommunication device.

The inventive system includes a plurality of sensors each monitoring adifferent parameter of the remote equipment. An interface unit isprovided having a PLC connected to the sensors; the PLC performs Booleanexpressions on signals received from the sensors and has a predeterminedconfiguration. The interface unit also has a message generatingmechanism. The system also includes a central computer server incommunication with the interface unit adapted to receive messagesgenerated by the interface unit. When the sensors detect an exceptioncondition in the remote equipment, the PLC of the interface unitperforms Boolean expressions on the signals in accordance with itspredetermined configuration, and the interface unit generates anincoming exception message and forwards the message to the server. Theserver forwards at least one outgoing exception message to at least onepredetermined user-defined communication device based on the incomingexception message.

The system can contact a customer or contractor via a number ofdifferent media (fax, email, pager, etc.) in case of an equipmentfailure. The contractor can determine which people to contact and whichmedium to use for which equipment failure. For example, if the conditionis not very serious (e.g., filter needs cleaning), the contractor canset up the system to send a message via e-mail; if, however, it isserious (e.g., low/high refrigerant pressure), then the system can pagethe contractor and/or send a text message over his personalcommunication service (PCS). Also, the system includes the capability tosend multiple messages to multiple recipients via differing mediasimultaneously for a given exception condition. Preferably, the systemincludes a centralized electronic message delivery device or server thatroutes the various incoming exception messages to the desiredindividuals via the desired electronic media in accordance with thepredetermined message profile. More preferably, the contractor orconsumer can access the centralized message server via the Internet andmodify the message profile through software on the device.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic of a preferred embodiment of a system according tothe invention.

FIG. 2 is a schematic of a preferred embodiment of a link between themonitored equipment and the system according to the invention.

FIGS. 3a-d are schematics of links between an end-user's machine and thesystem according to the invention.

FIG. 4 is a schematic of a preferred embodiment of the electronicmessage delivery server according to the invention.

FIG. 5 is a flow chart depicting the operation of the system accordingto the invention.

FIG. 6 is a schematic of a local RF network linking several pieces ofequipment together in accordance with an alternative embodiment of theinvention.

FIG. 7 is a ladder logic diagram in accordance with the invention for anexemplary air conditioning unit.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Equipment that needs to be monitored frequently, such as HVAC equipment,preferably operates within certain acceptable parameters. Some of theseparameters are more crucial to the operation and/or life span of theequipment than are other parameters. For example, a low batterycondition might be a lot less serious than a low coolant levelcondition. Whenever a piece of equipment operates outside its preferredparameters, an “exception” condition is created or said to exist. Anexception condition can also be indicative of a regularly scheduledevent occurring too often, too infrequently, or not at all. An exceptioncondition could also be indicative of a measured value being beyond thedesign specification for the equipment.

When a monitored piece of equipment detects an exception condition, itactivates its interface to the cellular phone network. The interfaceeffectively acts as a cell phone in a roaming condition. The interface“attempts” to make a telephone call; because it is not recognized asbeing a resident of the local cell, the local cell (via the cellularnetwork or mobile switching center) contacts the “home cell” of theinterface to insure that the interface is in good standing to completethe “call.” There really is no home cell; in actuality, what is takingthe place of the home cell of a cellular telephone is a message routingservice such as those provided by Aeris or Bell South Cellemetry. Whenthe local cell is contacting the message routing service, it transmitsthe following information: the serial number of the interface; themulti-digit “phone number” assigned to the interface; and themulti-digit phone number that the interface is “attempting to call.” Themessage routing service tells the local cell that the interface is okayand should not be blacklisted, that the call need not go through, andthat the interface should be removed from the “okay to roam” listimmediately.

The interface is not really trying to call anyone; the multi-digit phonenumber it was trying to call represents a multi-digit code ofinformation that is being sent to the message routing service and mayrepresent fault information (e.g., 212-555-1212 means “filter needscleaning”). The phone number assigned to the interface (which is alsosent along with the phone number it is “trying to contact”) may not onlyindicates which unit is doing the transmitting but may also convey faultinformation, since many of the devices being monitored do not have alarge number of different fault conditions. This type of technology, inwhich information is transmitted in the handshaking portion of acellular transmitter communicating to a local cell, appears in U.S. Pat.Nos. 5,594,740 to LaDue and U.S. Pat. No. 5,546,444 to Roach, Jr. etal., and is commonly referred to as using control channel data. In LaDue(the Aeris version), the exception or status information is embedded inthe digits of the “phone number” the interface is allegedly calling (the“dialed digits”); in Roach, Jr. (the Bell South Cellemetry version), theexception or status information is embedded in the electronic serialnumber (ESN) of the interface, a number which identifies the physicalhardware of the device. The information which identifies which interfacehas sent a message may be embedded in the mobile identification number(MIN) assigned to the interface unit. In the Aeris system, the ESN mayalso contain interface identification information.

The present invention expands on this technology and includes themessage delivery technique mentioned above. The Aeris or Bell SouthCellemetry router transmits the exception data to the inventive messagedelivery system which forwards the information to the contractor who isresponsible for maintaining the faulty equipment. The contractor isprovided with an account on the message delivery system that he canaccess via the Internet. The contractor sets up the specific parametersof which exception conditions are reported to which individuals. Thecontractor also sets up by which media (fax, e-mail, PCS) theseindividuals are to be notified. Multiple individuals may be alerted asto a exception condition. All of this data constitutes the contractor'smessage profile. For example, both the contractor and the owner of thepremises might be signaled if there is a low/high refrigerant condition,however perhaps only one of them would be notified if a filter requiredcleaning. The user may also set, as part of the message profile, thatdifferent messages be delivered to different individuals at differenttimes of the day, week, month, season, or year. For example, a highpriority exception message may be directed to one repair/maintenanceentity during regular business hours but be directed to a differentrepair/maintenance entity at night. Similarly, the same person could becontacted by different means (e.g., fax or PCS) at different times. Thecontent of the messages may also vary as a function of time.

In addition to notifying contractors when a problem arises, theinterface may be programmed to check in once a day with an “all systemsokay” message. This “okay” message also gets routed to the messagedelivery system. However, instead of being handled by an exceptionmessage subroutine in the message delivery system—the portion of thesystem which handles the above-mentioned fault messages—, the “okay”message is checked by a missing message subroutine. The missing messagesubroutine checks the entire list of HVAC interfaces that are supposedto signal “okay” from the message delivery system database. The missingmessage subroutine compares the entire list to the list of HVACinterfaces that actually checked in as “okay”. If an interface failed tocheck in “okay”, the message delivery system sends out the appropriatemessages to the proper individuals via the selected media, all inaccordance with the user's message profile lodged in the user's accountwith the message delivery system. The periodic “okay” or status messageis not merely limited to providing a status “heartbeat” for theequipment but may also be employed to transmit information about themonitored piece of equipment. As will be explained below, the statusmessage only requires a portion of its digits to convey equipmentidentification information, thus allowing other information to betransmitted as well. For example, the status message may includestatistical information about the equipment such as how many cycles ithas performed since the last message, the run time of the motor, etc.The status message may also serve as a reminder for routine maintenance,or it may report very minor or low-priority conditions that are not timesensitive.

The format of the message sent from the failing device to the local cellto the router to the message delivery system is a multi-digit code. Thefirst digit can be for message format (e.g., status message, exceptionmessage, etc.). The sub-address is a digit or two reserved to identifyto which unit that a transceiver interface is assigned is experiencingan exception condition; i.e., one transceiver interface may be assignedto a building having nine HVAC units, all connected to the transceivervia a bus line, or one interface may be part of a local RF network whereeach of multiple HVAC units has its own transmitter. The final digitswould indicate the specific exception condition. The multi-digit messagereceived by the message delivery system is normalized, converted into aregular text message, and forwarded to the user/contractor. Informationcan also include model, brand, installation date, and climate andweather data for the site. Alternatively, much of this type of equipmentcriteria can be stored at the central data base so that only theequipment identification information need be transmitted.

A number of pieces of equipment may be linked to a single cellularinterface via a local RF network. This is advantageous because manybuildings have multiple pieces of HVAC equipment, and the provision ofeach piece with its own cellular interface is expensive. The deploymentof a local RF network is also advantageous when the multiple HVAC unitsare fairly remote and a hardwired connection to a common bus line wouldbe impractical or impossible.

Description will now be given of the preferred embodiments withreference to FIGS. 1-7. FIG. 1 shows an overall view of the inventivesystem 50. An existing piece of equipment may be monitored, for example;an air-conditioner 2, boiler 3, motor starter 4, heater 5, or any otherpiece of equipment they may be desired to be monitored. The existingpiece of equipment is fitted with an interface unit 10. Periodically,the interface unit 10 sends to the message delivery server 1 a statussignal to let the message delivery server 1 know that the equipmentbeing monitored and the interface unit 10 are functioning correctly.When a predetermined exception condition occurs in the piece ofequipment being monitored, the interface unit 10 sends an incomingexception message to the message delivery server 1. The message deliveryserver 1 then routes the message as an outgoing exception message to theappropriate user interface; e-mail 6, fax 7, pager 8, voice 9, etc.,according to the message profile as configured by the user of the system21 via the Internet 122.

The inventive system can be deployed on existing pieces of remoteequipment. Various sensors can be added to an air conditioner, a boiler,etc. that can detect various conditions. For example, in an airconditioner, different sensors can be provided throughout the systemeach to detect a different condition such as low or high pressure, acondensate spill, air flow, fan motion, compressor function, etc. Anyand all conventional sensors are contemplated as being usable in theinvention, including but not limited to pressure sensors, pitot tubes,motion sensors, photosensors, electrical resistance sensors, moisturesensors, magnetic sensors, and the like.

Whether the sensors are built into the HVAC unit or added later, thevarious sensors in a monitored piece of equipment are preferablyarranged in ladder logic configurations in programmable logiccontrollers (PLCs). Each sensor is responsible for detecting a certaincondition or monitoring a certain parameter. These sensors can begrouped via Boolean logic operators (AND, OR, XOR, NOT, etc.) to providethe circumstances under which an exception condition is defined.

An example of such a ladder logic PLC for a typical air conditioningunit is shown in FIG. 7. Each of sensors 602-609 monitors a differentcondition/parameter of the unit. Sensor 604 detects low pressure in thecoolant, sensor 605 detects high pressure in the coolant, sensor 606detects if the fan is working, sensor 607 detects if the compressor isworking, sensor 608 determines if a condensate spill has occurred, andsensor 609 detects if the compressor is working. Some of the logic isdirect and simple. For example, if sensor 605 detects a high pressurecondition, high pressure message 101 is sent via the message generatingmechanism of interface unit 10. Similarly, if sensor 608 detects acondensate spill, message 102 is sent.

Other rungs of the ladder are more complex. For example, in line F, ifsensor 606 detects that the fan is working, timer 1 is activated; if noair flow is detected by sensor 609 before timer 1 times out, the “no airflow” message 104 is sent. If, in line H, sensor 606 detects no fanoperation and sensor 609 detects no air flow but sensor 607 detectsproper compressor function, and timer 3 times out, “compressor w/no fanor air flow” message 105 is sent (line I). As another example, message107 is sent out if sensor 602 detects a logic 0 in “aux 1” input and dipswitch 4 is closed (logic 1) by activating relay 1 in line P.Alternatively, if sensor 602 detects a logic 1 in “aux 1” and dip switch4 is open (logic 0), a message will be sent. In either case, a message107 is sent in line O.

The dip switches are provided to allow certain portions of the logic tobe disabled if a customer is not interested in receiving a certain typeof message. For example, a sensor could be set to detect if a compressoris cycling fast and to send a “fast cycle” message in that event.However, if the user has the compressor deliberately set up to cyclefast, the user will not want to receive a constant stream of messagesinforming him that the compressor is cycling fast. Instead, a dip switchcan be set to disable that message from being sent. The conventional dipswitch is adjustable on-site. The invention contemplates also enablingthe user to set up virtual dip switches via the Internet at a centralserver as will be explained below.

Each PLC can be different for each unit, type of unit, brand, model,etc. The PLC may by hard wired at the remote installation site.Alternatively, the various sensors can be linked via computer softwareat a web site that interacts with system 21. For example, instead ofsending out a low pressure message 100 for a low pressure condition anda high pressure message 101 for a high pressure condition, a user can ORthe outputs of sensors 604 and 605 together for the sending out of an“abnormal pressure” message. A user can adjust a logic ladder in thesame or similar fashion as one would edit a message profile, e.g., bymenu-driven websites, by an automated telephone response system, etc.The user can, of course, request an initial hardwired configuration ofthe system installer and have that adjusted on-site as needed.

In FIG. 1, each piece of equipment 1-4 is provided with its owninterface unit 10. An alternative configuration is shown in FIG. 6. Asshown in FIG. 6, four air conditioners 2A-D are each provided withsensor 600 (which generically represents any of sensors 602-609 and anylike sensors) and an RF transmitter 601. When an exception condition isdetected by sensor 600, or if after a certain period of time, noexception condition is detected, transmitter 601 transmits an RF signal610 to a common interface unit 10′. Common interface unit 10′ includesantenna A for receiving signals 610. Unit 10′ sends incoming messages tothe electronic message delivery server 1 via link 11 in the same manneras shown in FIG. 1.

Messages from some of the interface units 10 may be delivered by meansof wireless transmission over the cellular telephone network (see U.S.Pat. Nos. 5,594,740 and 5,546,444). FIG. 2 is a detailed view of link 11shown in FIG. 1. A message is transmitted from the cellular interfaceunit 10 a via a radio frequency link 13 to a nearby cellular transceiversite 14, the message is then routed to the cellular network or mobileswitching center (MSC, e.g., a cellular carrier such as Bell Atlantic)16 where the message is then delivered via data circuits 17 and viarouter 51 (e.g., Bell South Cellemetry or Aeris) to the message deliveryserver 1. As will be clear from the discussion of FIG. 4, referencenumerals 11 a and 11 b refer to different types of links. Specifically,link 11 a is for receiving incoming exception and status messages frominterfaces 10 which are in regions wired for sending data via the dialeddigits control channel; link 11 b forwards messages along the ESNchannel to the message server 1.

Based on the configuration of the user's message profile, the outgoingexception message (or messages) is then delivered to the specified enddevice or devices. FIGS. 3a-d show a more detailed view of the variousoutbound links 12 a-d that connect the server 1 to the variouselectronic media. In FIG. 3a, server 1 sends the message over atelephone line 18 a to the Internet 122 and deposits the message in theuser's e-mail box 6. In FIG. 3b, server 1 sends the message over atelephone line 18 b through the public telephone switched network (PTSN)19 to the user's fax machine 7. In FIG. 3c, server 1 sends the messageover a telephone line 18 c to the user's pager service 53 and thence tothe user's pager or PCS 8. In FIG. 3d, server 1 sends the message over atelephone line 18 d through the PTSN 19 to the user's voice mail box 9.The same message may also be sent to a number of other devices asconfigured by the user 121 over the Internet 122. The same message thatis being sent to a fax machine 7 as described above may alsosimultaneously be sent to an e-mail 6 recipient via the Internet.Preferably, different messages can be sent to different individualssimultaneously for the same fault condition; for example, the owner ofthe premises may receive a less-detailed message than the contractor.

A user's message profile can also be configured to store messages onserver 1 for delivery at a later time or after certain conditions aremet. For example, a contractor may not want his beeper activated everytime server 1 receives an incoming exception message. The user profilecan be configured to deliver messages on groups or only after severalmessages have accumulated for the same user/contractor. Optionally, anoutgoing exception message may be generated only after several of thesame type of incoming message are received; a portion of the memory ofserver 1 may be devoted to the storing and/or accumulating of messages.Alternatively, a single outgoing exception message may be generated inresponse to several incoming messages.

In the same way the user profile can be configured, the user canconfigure virtual dip switches to enable or disable certain errormessages. Conventional hardwired dip switches must be adjusted on siteat the remote equipment. Virtual dip switches are software subroutinesstored in server 1 which allow the user to toggle on or off certainportions of the ladder logic of the PLCs controlling the sensors of theremote equipment. According to the invention, the user can go to awebsite on the Internet 122 and, through menu-driven commands, enable ordisable sections of the ladder logic just as he would be able to byflipping conventional dip switches at the installation site of theremote equipment. Additionally, the user will be able to configure thelogic of the PLC remotely via the Internet as well.

A user may also control the functioning of a remote device in this way,via the Internet. The user can enter commands at the website or otherInternet interface, and those commands are forwarded to the server 1. Inaccordance with the user profile, for example, in the same way thatexception messages are sent out via links 12 a-d, a command message maybe sent to the remote device through interface unit 10. Such commandmessages allow the user to activate, deactivate, and otherwise controlthe appliance. The interface unit 10 can receive these command messagesbecause the means by which the unit 10 communicates with the server,e.g., the cellular telephone network, is bi-directional. As a result ofthis bi-directionality, incoming links 11 a-d may also be used tocommunicate with the devices through their respective interface units10.

FIG. 4 shows the details of the message delivery server 1. In thepreferred embodiment, server 1 includes four hardware devices 200, 300,400, and 500. Device 200 is responsible for receiving incoming messages,processing them in accordance with the user's preferences, and routingthem for output. Messages may be temporarily stored or accumulated ondevice 200 before being transmitted to the user if the user's messageprofile is set up accordingly. Device 300 enables the user 121 to accessserver 1 and create or edit his message profile residing in relationaldata base 21 of device 200. Device 400 includes the various drivers 33which are responsible for transmitting the various messages to thevarious media (fax, e-mail, etc.). Device 500 includes billing computer38 for keeping track of the charges and fees associated with the user'suse of the service.

At the core of server 1 is a relational data base 21. Incoming messagesare received by a specific service designed to handle both the transportmethod and message formatting. Every interface unit 10 is provided, likea cellular telephone, with an electronic serial number (ESN, to identifythe specific interface unit sending the message) and a mobileidentification number (MIN, similar to a cellular telephone's phonenumber). In some instances, the exception or status information isembedded in the dialed digits the interface transmits. The dialed digitscontrol channel module 25 specifically receives messages that areencoded in the control channel's dialed digits (see U.S. Pat. No.5,594,740). The ESN control channel module 24 receives messages that areencode in the electronic serial number of the message (U.S. Pat. No.5,546,444). It is preferable to have both a dialed digits module 25 andan ESN module 24, because some geographic regions employ dialed digitdata coding, while other regions employ ESN data coding. Information maybe transmitted via the MIN of the interface 10 and also received bymessage delivery server 1. Services are also available to receivemessages for analog modems connected to the public telephone switchednetwork 23, and the cellular digital packet data network 22. Asadditional methods of transmitting data become available, they can beadded to the services layer.

All incoming messages are normalized at the normalization module 26 sothat all incoming messages can then be processed without regard to theirincoming medium. All incoming messages are passed to the normal messagesubroutine 27, exception messages are passed on for processing androuting via the user's configuration through the data base 21, andperiodic status messages are queued. The missing message subroutine 28compares received status messages with a list of expected messages.Status messages that are not received have an error message generated bythe missing message subroutine 28 which are then delivered as configuredby the user in his message profile as recorded in the relationaldatabase 21.

Messages to be delivered are placed in a message queue 32; as messagetraffic permits the appropriate drivers 33 request messages from themessage queue 32 and route the messages over the appropriate transport.Numeric pages, faxes, voice and DTMF 34 are sent over the PTSN 12 b-d,e-mail 35 is sent over the Internet 122. When a driver 33 hassuccessfully delivered, a record is made in the data base 21 by thedelivery confirmation subroutine 31 showing time and date of successfuldeliveries. Undeliverable messages are routed back to the database forgeneration of undeliverable message errors.

Users 121 connect to an Internet information server 30 via the Internet122. The Internet information server presents to the user theinformation pertaining to that user's interfaces. Requests to alter theuser's data are passed through active server pages 29 to protect boththe integrity and security of the data base 21. All messages andtransactions that pass through the system are logged in section 36, thetransaction and message logs are then interfaced by section 37 to abilling system 38.

A portion of the memory in relational data base 21 is preferably used tocompile data regarding the devices being monitored over time. Such datais sortable by any number of different criteria, including brand ofequipment, specific models of equipment, installation date (and thus theage of the equipment), the general local climate in which the equipmentis installed (e.g., arid, humid, warm, rainy, etc.), local weatherconditions in a given period of time, and the like. This information isusable in a number of different ways. A user can log in via theInternet, for example, and find out the maintenance history of hisspecific units to see which are the most reliable or most unreliable.Alternatively, a user can check to see which brands or models generallyare the most reliable for any given conditions (age, climate, weather,etc.). Additionally, the information may be collated and processed bythe operator of data base 21 and published by any number of differentcriteria. Any of the various messages may be stored for this purpose,e.g., the incoming messages from the interface units, the normalizedmessages output from the normalization module, the outgoing messages,normal status messages, etc.

An example of the system's operation is as follows. When auser-contractor 121 first signs up with the system 50, he receives anaccount on the electronic message delivery server 1. Via the Internet,the contractor 121 is prompted through software to enter the pagernumbers, cellular telephone numbers, facsimile machine numbers, andInternet addresses of any individuals who are to be contacted in theevent of an exception condition in building equipment 2-5 for which thecontractor is responsible. The user-contractor 121 may also set thesoftware to notify him of the periodic successful routine status checkmessages conveyed from equipment 2-5.

FIG. 5 depicts a flow chart of the basic steps that occur when a messageis received by server 1. At step S1, the message is received. At stepS2, normalization module 26 removes the required elements from theincoming message and arranges them in a normalized format and storesthem as a record in a table. Server 1 can now examine a specific elementin a message of any received media type. At step S3, it is determinedwhat type of error message has been received. If it is an exceptionmessage that requires immediate action, it is passed onto a process tobegin configuration of a readable message at step S4 for delivery atstep S5. If not, server 1 determines if the received message is a “unitchecking in” or a “system ok” status message at step S6. If the user hashis message profile so configured, a storing/accumulating step (notshown) may occur between steps S4 and S5. Undefined messages are handledat step S7. If it is configured as a periodic message received toindicate normal operation of a unit, the message is stored at step S8for use at a later time. Periodically, the list of units that havereported in at step S8 and the list of active units expected to reportin (part of database 21) are compared at step S9. Units on the activelist that do not appear on the checked-in units list are processed, andunits that failed to report in have messages created at step S10. Thesemessages are then posted for further processing and message delivery atstep S5.

In the example given, suppose boiler 3 breaks down in a non-catastrophicmanner. The fault condition is detected by a sensor (not shown) andencoded to interface 10. Interface 10 transmits a radio message via link13 to a local cell site 14, which contacts data circuits 17 via cellularnetwork 16. Circuits 17 forward the message to message server 1. If themessage is transmitted by the cellular telephone network 16, the ESNarrives via link 11 b to ESN channel 24; alternatively, the dialeddigits information arrives via link 11 a to dialed digits channel 25.The message is normalized in normalization module 26 and passed along tothe normalized message process module 27. Module 27 selects the user'smessage profile from relational database 21 and in accordance therewith,determines what message gets sent to whom and by which medium.Alternatively or in addition, multiple fault conditions may be linkedtogether via user-configurable ladder logic.

The invention is not limited to the above description but rather isdefined by the claims appearing hereinbelow. Modifications to the abovedescription that include that which is known in the art are well withinthe scope of the contemplated invention. For example, the invention isdesigned to be adaptable to all forms of electronic communication, bethey cellular telephone, land line telephone, electronic mail,facsimile, text page, voice mail, etc. All forms of electronic media arecontemplated as being within the scope of the invention. Also, multipleformats of incoming and outgoing messages are contemplated as includedwithin the scope of the claims and the invention. The user can adjustthe format and content of the messages he receives by setting up hismessage profile accordingly. The invention is also not limited to use inmonitoring HVAC equipment but is contemplated to be useful formaintaining all forms of remote equipment. For example, the inventivesystem and method would prove extremely expedient is monitoring andreplacing warning lights on cellular towers, radio transmitter towers,and other remote structures.

What is claimed is:
 1. A system for monitoring at least one piece ofremote equipment, comprising: at least one sensor monitoring at leastone parameter of the remote equipment; a bi-directional interface unitconnected to said sensors and the remote equipment, said interface unithaving a message generating mechanism that generates messages based ondata received from said sensor; a central computer server incommunication with said interface unit, said server adapted to receivemessages generated by said interface unit and said interface unitadapted to receive command messages from said server; and an Internetinterface linked to said central computer server and selectivelyremotely accessible by users via the Internet, wherein when a userenters a command into said Internet interface, said Internet interfacetransmits said command messages to said central computer server and saidcentral computer server transmits said command messages to said remoteequipment, said command messages including at least one of commands toactivate, commands to deactivate, and commands to alter the functioningof the remote equipment, and wherein when said sensor detects anexception condition in the remote equipment, said interface unitgenerates an incoming exception message and forwards said message tosaid server, and wherein said server forwards at least one outgoingexception message to at least one predetermined user-definedcommunication device based on said incoming exception message.
 2. Amethod of monitoring remote equipment comprising the steps of: a)determining respective states of a plurality of parameters of at leastone piece of remote equipment via a plurality of sensors; b) groupinginformation from the sensors via ladder logic; c) communicating messagesregarding the grouped information from the remote equipment to a centrallocation as incoming messages; and d) forwarding outgoing exceptionmessages based on the incoming messages to at least one user-definedcommunication device.
 3. A method according to claim 2, wherein saidstep b) further comprises the step of using a programmable logiccontrollers (PLC) to perform Boolean expressions on the informationdetected from the sensors.
 4. A method according to claim 3, whereinsaid step c) further comprises the step of communicating said messagesvia at least one of a cellular telephone network, radio transmissions,telephone lines, and the Internet.
 5. A method according to claim 3,wherein the PLC is remotely user-configurable via the Internet.
 6. Amethod according to claim 2, further comprising the step of providing aportion of the message with equipment identification information.
 7. Amethod according to claim 2, further comprising the step of e)determining whether an incoming message is an incoming exception messageor a normal status message.
 8. A method according to claim 7, wherein,if an incoming message is determined to be an incoming exception messagein step e), the method further comprises the step of f) routing theincoming exception message as the outgoing exception message to the atleast one user-defined communication device.
 9. A method according toclaim 8, further comprising the step of g) creating a user-definedmessage profile, wherein said forwarding step d) forwards the outgoingexception message in accordance with the user-defined message profile.10. A method according to claim 7, wherein if the incoming message isdetermined in step e) to be a normal status message, the method furthercomprises the step of h) storing the normal status message in a normalstatus memory.
 11. A method according to claim 10, further comprisingthe steps of: i) providing a main list of all pieces of remote equipmentbeing monitored; j) comparing the normal status memory with the mainlist to determine which pieces of remote equipment did not communicate anormal status message within a predetermined period of time; and k)generating an outgoing exception message for each piece of equipmentidentified in step j).
 12. A method according to claim 9, wherein stepd) further comprises forwarding multiple outgoing exception messages tomultiple user-defined communication devices in response to a singleincoming message in accordance with the user-defined message profile.13. A method according to claim 9, wherein step d) further comprisesforwarding a single outgoing exception message to a user-definedcommunication device in response to multiple incoming messages inaccordance with the user-defined message profile.
 14. A method accordingto claim 9, further comprising the step of 1) storing a plurality ofuser-defined message profiles at the central location.
 15. A methodaccording to claim 2, wherein the remote equipment includes heating,ventilating, and cooling equipment.
 16. A method according to claim 6,wherein said step d) further comprises the step of forwarding theequipment identification information to the at least one user-definedcommunication device.
 17. A method according to claim 2, furthercomprising the steps of: communicating command messages from the centrallocation to the remote equipment; and controlling the functioning of theremote equipment via the command messages.
 18. A system for monitoringat least one piece of remote equipment, comprising: a plurality ofsensors each monitoring a different parameter of remote equipment; aninterface unit connected to said sensors having a programmable logiccontroller (PLC) for performing Boolean expressions on signals receivedfrom said sensors, said PLC having a predetermined configuration, saidinterface unit having a message generating mechanism; and a centralcomputer server in communication with said interface unit, said serveradapted to receive messages generated by said interface unit, whereinwhen said sensors detect an exception condition in the remote equipment,said PLC of said interface unit performs Boolean expressions on saidsignals in accordance with said predetermined configuration, and saidinterface unit generates an incoming exception message and forwards saidmessage to said server, and wherein said server forwards at least oneoutgoing exception message to at least one predetermined user-definedcommunication device based on said incoming exception message.
 19. Asystem according to claim 18, wherein said message generating mechanismforwards said incoming exception messages via at least one of aplurality of communication media, said media comprising at least one ofa cellular telephone network, radio transmissions, telephone lines, andthe Internet.
 20. A system according to claim 19, said server comprisinga normalization module, wherein said server receives said incomingexception messages from said interface unit and said normalizationmodule normalizes said incoming exception messages into a uniform formatto create normalized messages, wherein said outgoing exception messagesare generated based on said normalized messages.
 21. A system accordingto claim 18, further comprising at least one dip switch connected tosaid PLC and interconnected between said sensors, said dip switchselectively switchable between an open position and a closed position,wherein said dip switch can selectively disable portions of said PLC.22. A system according to claim 18, further comprising at least onevirtual dip switch in said central computer server which can selectivelydisable said outgoing exception messages.
 23. A system according toclaim 22, wherein said at least one virtual dip switch is selectivelyswitchable by a user via the Internet.
 24. A system according to claim18, said system monitoring a plurality of pieces of equipment, eachpiece having an identification code, said server further comprising: afirst memory on which equipment identification codes of all monitoredequipment are stored; and a second memory in which communication deviceidentification codes of all of said user-defined communication devicesare stored, said communication device identification codes beingconfigured in user-defined message profiles.
 25. A system according toclaim 24, wherein said interface unit periodically generates a normalstatus message if its respective pieces of equipment are functioningproperly, said normal status message including an interface unitidentification code.
 26. A system according to claim 25, said serverfurther comprises: a fourth memory for storing said normal statusmessages; means for comparing the normal status memory with the mainlist and for identifying which of said pieces of remote equipment didnot communicate a normal status message within a predetermined period oftime; and means for generating and forwarding an outgoing exceptionmessage for each piece of equipment identified by said comparing andidentifying means, said outgoing exception message being forwarded to atleast one of said user-defined communication devices in accordance withat least one of said user-defined message profiles.
 27. A systemaccording to claim 18, wherein the monitored equipment is remoteheating, ventilating, or cooling equipment.
 28. A system according toclaim 18, further comprising: an Internet interface linked to saidcentral computer server and selectively remotely accessible by users viathe Internet, said Internet interface enabling users to transmit commandmessages to said central computer server, wherein said interface unit isbi-directional and can receive said command messages, and wherein when auser enters a command into said Internet interface, said Internetinterface transmits said command messages to said central computerserver and said central computer server transmits said command messagesto said remote equipment.
 29. A system according to claim 28, whereinsaid command messages include at least one of commands to activate,commands to deactivate, and commands to alter the functioning of theremote equipment.